Britain has formally requested the extradition from Pakistan of a man described as a "key figure" in the alleged terrorist plot to attack transatlantic airliners.

The return of Rashid Rauf, 25, has been sought in connection with the murder of his uncle Mohammed Saeed, 54, who was stabbed to death in Birmingham in April 2002.

But it is expected that he will be questioned about claims that he was involved in planning and financing the alleged plot to detonate suicide bombs on several aircraft in mid-flight.

A Home Office spokesman said: "The United Kingdom has put in an extradition request to the Pakistani authorities in respect of a murder committed in April 2002. We cannot confirm or deny the existence of any further extradition requests."

There is no formal extradition treaty between Britain and Pakistan but arrangements are in place which allow for one-off transfers of prisoners.

Tasnim Aslam, a Pakistani Foreign Ministry spokeswoman, said that Mr Rauf was being investigated for alleged links with al-Qaeda, in connection with terrorist threats in Britain and in Pakistan.

Asked if the British Government had sought Mr Rauf’s extradition, she told a news conference: "Yes, they have sought his extradition and the matter is under consideration."

Mr Rauf's brother, Tayib, 22, was arrested earlier this month in anti-terrorist raid in Birmingham but was later released without charge. His father, Abdul, was a founder of the charity Crescent Relief, which is under investigation by the Charity Commission following allegations that funds may have been diverted for terrorist purposes.

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